I don't think Cristiano Ronaldo would ever think of partnering up with an exchange and let his huge fan following know about blockchain and digital collectibles if it wasn't because of NFTs.
So, even though Bitcoin is the largest and the most popular one, other cryptocurrencies also have some utility and importance in the wide world of blockchain technology.
To talk about altcoin, apart from Ethereum, I almost did not see any altcoin with utility or can be used to apply in practice as they advertise. What I see in the Altcoin market right now are pumping and dumping, nothing more than that. I do not deny that the cryptocurrency industry wants to develop, it will need altcoins, but now it is not the time to trust them, all is just a hyped and disappearing game. Crypto is still a more speculative market than creating the technologies of the future we still think.